Using human induced pluripotent stem cells to investigate neurodevelopmental effects of human cytomegalovirus

Human cytomegalovirus (HCMV) is one of the leading prenatal causes of mental retardation and congenital deformities, world-wide. Its pathogenesis has generally been investigated using animal models. Human studies in vitro have been limited to neurospheres prepared using forebrain tissues from fetal abortuses. This approach is limited and does not permit analysis of individual specific cells. We generated iPS cells from adult human fibroblasts. iPS cells were differentiated into neurospheres, that were expanded as monolayer culture of neuroprogenitors (NPs). Furthermore, neurospheres were differentiated into neurons that could be stained for Tuj1, tyrosine hydroxylase and NR4A2. Functional competency was confirmed by live imaging of intracellular calcium. NPs and neurons were infected with HCMV (MOI = 3). Cell viability was assessed by FACS analysis. Cytopathic effects of HCMV were observed on the 10th day post infection in neuroprogenitor cells. Earlier, the adherence of these cells to the matrix was reduced. Neurons were much more refractory. Reduced cell density and shortening of neuritic processes was only observed at day 15 after infection. We are presently examining the intracellular effects of HCMV. Human iPS cells can efficiently generate neurospheres, which can be expanded as almost pure cultures of neuroprogenitors or differentiated into neurons. iPS cells-derived NP and neurons offer powerful cellular models to investigate the effect of neurotropic viral agents on neurodevelopment